DTE Energy, a Detroit-based diversified energy company, has now enrolled 4,000 customers in its GreenCurrents renewable energy plan since the program launched in April.

GreenCurrents allows customers to purchase a block of renewable energy equal to 15% to 20% of a typical home's monthly electric usage or match 100% of the home's electricity consumption with renewable resources by paying an extra $10 to $15 per month for a typical household, DTE Energy says. The company uses renewable energy derived from wind, biomass and other sources.